FC: No, something like that would require extensive changes to the levels, to prevent players from climbing out of the geometry.

ML: More importantly, it would run counter to what we were trying to do with Killzone. The omission of the ‘jump’ button was a very deliberate design decision, almost like a statement against other shooters of the time. We wanted players to have a visceral, realistic experience, and that meant preventing them from traversing our game by bunny-hopping or rocket-jumping. Even when we re-introduced jumps for the obstacle-heavy terrains in Killzone 2, they were ‘weighty’ jumps – not perfect parabolic arcs, but the sort of short leaps a heavily packed soldier would make.

Along with the HD upgrade, they also talked about how the development team went through the original code from the game and fixed some bugs that were shipped with the PS2 version:

ML: The Offices level from chapter 2 is a good example. In the original, there were a couple of pillars that the player could just walk right through. The bug slipped by us due to a very, very late change to the content.

FC: I remember how [Killzone 3 producer] Seb Downie really despaired over that one. He was our QA Manager back then, and the poor fellow discovered the bug right after Killzone had gone to gold master, so there wasn’t any time left to fix it.

Aside from the bug fixes and HD conversion, you can also expect full trophy support, an updated control scheme, and the following:

FC: Where possible, the Killzone assets we retrieved have been resampled or recreated at a higher resolution. Textures, for instance, were originally designed at twice the required size and then downscaled to fit into PlayStation 2 memory. For PlayStation 3 that’s no longer a concern, so the game uses the full-sized textures. Similarly, the menus and HUD-elements have all been upscaled and reworked to look good in 720p.

ML: A lot of the improvements to the game have been facilitated by switching to the more powerful PlayStation 3 hardware. The frame rate is smoother, the shaders are of a better quality, the LOD settings have been tweaked to nearly always show the highest level of detail, and the engine now applies MSAA filtering – which, by the way, looks really sharp on a lower-polygon title like Killzone.

Lastly, they revealed in the comments that there isn’t a demo planned for Killzone HD, meaning that you’ll have to buy the game on its own or pick up the Killzone Trilogyif you want to play it.